Due to a quirk in the method as currently written, Method 25A allows for continued calibration drift from run-to-run that can result in the post-test drift check value at the end of Run 2 or 3 exceeding the pre-test calibration error criteria and still be technically considered a valid test run. This will be corrected in an upcoming method revision, but in the interim until such time, EMS will require that the post-test drift check values at the conclusion of each test run also meet the pre-test calibration error criteria. Failure to demonstrate this will either invalidate the run, or the facility can elect to do (at risk), a Method 7E drift correction (Method 7E calls this a bias correction, but it really is a drift correction) for the run in question. In either case, a full recalibration is required prior to conducting additional test runs.